Once you have your germinated seeds or small plants, it’s time to place them in containers with well-draining soil and at least one drainage hole so water can escape. “You have to make sure your plant is never, ever standing in water,” Viljoen stresses, as soaked roots can develop root rot and die.
For this reason, delicate decorative planters that don’t have drainage holes aren’t the best pick for an outdoor garden. Instead, go with strong and sturdy but portable materials like terracotta, fiberglass, or aluminum for easy maneuvering.
Palmer recommends using as large of a container as you can comfortably put in your space: It will fit more soil (and therefore need to be watered less frequently) and leave more room for different varieties of plants to grow side-by-side. “I tend to mix lots of different varieties so that I’m not going to be left with a patch,” she says.
She suggests placing four or five plants in a 25 to 30 cm. planter (approx. 9 to 11 inches), six or seven plants in a 30 to 40 cm. planter (approx. 11 to 15 inches), and eight or nine plants in a 40 to 50 cm. planter (approx. 15 to 19 inches).
Again, place plants with similar water and light needs in the same pot and put taller plants in the back, shorter ones upfront.